Brake cylinder device



B. S. AIKMAN BRAKE CYLINDER DEVICE March 26, 1940.

Original Filed Sept. 11, 1937 .H @hr ATTORN EY A RM mM Mw T H U .B

Patented Mar. 26, 1940 UNITED STATES PATENT OFFICE BRAKE CYLINDER DEVICE Original application September 11, 1937, Serial 163,390. Divided and this application April 14, 1938, Serial No. 202,141

11 Claims.

This invention relates to fluid pressure brake equipment and more particularly to brake cylinder devices which form a part thereof and which are operative by fluid under pressure for eiecting an application of the brakes, this application being a division of my copending application, Serial No.'163,390, filed September 1l, 1937.

The usual brake cylinder device comprises a single acting p iston slidably mounted in a cylinder body, and a push rod carried by the piston and slidably mounted in a non-pressure head secured to one end of the body. 1n order to prevent excessive wear of these parts of a brake cylinder device and maintain such parts in condition to work freely, and also to maintain the fit between the piston and cylinder as leak tight as possible, it is desirable to maintain these parts adequately lubricated.

The principal object of the invention is therefore to provide an improved, automatic lubricating system for the working parts of a brake cylinder device.

Other objects and advantages will be apparent from the following more detailed description of the invention.

In the accompanying drawing: Fig. 1 is a sectional view of a brake cylinder device embodying the improved lubricating system; and Fig. 2 is a sectional view of a cap adapted to be employed in connection with a portion of the apparatus shown in Fig. l.

As shown in the drawing, the improved brake cylinder device comprises a cylindrical body |51 having a bore in which there is disposed a brake cylinder piston |52, the bore at one end being closed by a pressure head |53 and at the opposite end by a non-pressure head |54. The piston |52' has at one side a pressure chamber |68 connected to a pipe 200 through which fluid under pressure is adapted to be supplied to said chamber for effecting an application of the brakes and through which fluid under pressure is adapted to be released from said chamber for effecting a release of the brakes, in the usual manner. The piston |52 has at the opposite side a non-pressure chamber -open to the atmosphere through a breather passage 202 over which a strainer |4 is provided for preventing dirt or other foreign matter entering said chamber.

The piston |52 has a hollow rod |55 secured to the low pressure face thereof and said rod is slidably mounted in a suitable bore provided through the end of the non-pressure head |54. A return spring |56 is interposed between the low pressure face of the piston |52 and the non-pressure head |54 for urging the piston |52 to its release position, as shown in the drawing.

A packing cup is secured to the inside of the non-pressure head |54 and has an outwardly ared skirt portion |51 in sealing engagement 5 with the periphery of the piston rod |55 while to the outer end of the non-pressure head |54 there is secured a packing cup having an inwardly flared skirt portion |58 effecting sealing engagement with the periphery of the piston rod |55 and an oppositely flared skirt portion |59 also effecting sealing engagement with said rod. The skirt portion |59 is provided to prevent the entrance of foreign matter between the skirt |58 and the piston rod |55 which would tend to force the skirt |58 out of sealing engagement with the rod |55 and thereby permit leakage past the skirt |58. It will be noted that the skirts |51 and |58 of the two packing cups are oppositely disposed so as to prevent leakage from between said cups out along the piston rod |55.

The piston |52 comprises a piston head |60 to which is secured a suitable packing cup |6| having an outwardly flaring skirt portion 203 slidably contacting the wall of the cylinder. Back 25 of the skirt portion 203 an annular groove is provided in the peripheral face of the piston and in this groove is an annular packing |62 which is substantially L-shaped in cross-section and so disposed that one leg portion of the packing flares outwardly into sealing engagement with the wall of the piston cylinder. Between this leg, portion of packing |62 and the adjacent portion of the piston packing 16| there is an annular space |63 in which there is disposed any suitable lubricant absorbing material |64, such for example as in the form of a felt ring. y

A lubricant pump piston |65 is slidably mounted in a suitable bore in the pressure head |53 in axial alignment with the brake cylinder piston 40 |52. One side of this puqmp piston is subject to pressure in chamber |86 at the pressure side of the brake cylinder piston |60, while the opposite side is open to a chamber |66 in which there is disposed a spring |61 which acts on the pump piston urging same in the direction toward the application position of thebrake cylinder piston |52. An annular collar |68 is provided on the end of the piston |65 in chamber |66 and is adapted to engage a shoulder |69 provided on the pressure 50 head for limiting outward movement of the piston |65, which will be hereinafter described.

The chamber |66 is open past a discharge valve 205, which Vis subject to the pressure of a light bias spring 206, to a passage 201 which extends 55 upwardly through the pressure head |53 to a point where it is connected to a passage |1| extending lengthwise through the top o1' the brake.

cylinder body |5|. The passage |1| is connected through a pipe |12 secured in suitable bosses provided on the non-pressure head |54 to a passage |13 in the non-pressure head which leads to a. passage |14 therein. One end of the passage |14 leads to the pressure face of the packing cup skirt |51 and to an annular groove |15 open to and surrounding the outer periphery of the piston rod |55, while the other end of the passage |14 opens to the pressure face of the packing cup skirt |58 and to an annular passage |16 open to and surrounding the outer periphery of said piston rod.

A chamber |69a provided above'and open to passage |1| is provided with an opening, normally closed by a plug |11, for the insertion of a stand pipe |18 into the brake cylinder body |5| for establishing communication from said chamber to the annular chamber |63 in the brake cylinder piston |52, when said piston is in release position, as shown in the drawing. This pipe extends somewhat above the level of the top wall of the passage |1| for reasons which will be hereinafter explained.

A removable lubricant reservoir |19 is secured to a depending boss on the brake cylinder body |5| by screw-threaded engagement. Asuction pipe |8| secured to the brake cylinder body |5| Within the boss |80 extends to near the bottom of the reservoir |19. In the upper end of this pipe there is disposed an inlet check valve |82 and a light spring |83 acting on said check valve for seating same. The space |84 above the check valve |82 is connected through a pipe |85 to a passage |86 which leads to the pump piston chamber |66'.

A passage |81 is provided in the lowermost portion of the brake cylinder body, |5| leading from the pressure chamber |88 in front of the brake cylinder piston |60 to the lubricant reservoir |19. The brake cylinder body |5| is also provided with a port |89 in its lowermost portion adapted to connect to the chamber |63 in the brake cylinder piston when said piston is in its release position, as shown in the drawing. A check valve |90, subject to the pressure of a spring |9 is provided in the brake cylinder body for controlling communication from passage |89 to a passage |92 which is also open to the lubricant reservoir |19.

The operation of the brake cylinder device just described is as follows: Whenever the brake cylinder piston |52 is moved in a direction toward the right hand by fluid under pressure supplied through pipe 200 to the chamber |88, in order to effect an application of the brakes, the spring |61 moves the pump piston |65 in the same direction until the collar |68 thereon engages the shoulder |69 in the casing. During this movement of the pump piston |65, it draws lubricant from the reservoir 19 up through the intake pipe |8| and past the check valve |82 into passage |86 and chamber |66 at the left hand side thereof. At the end of this intake stroke of the pump piston |65 the pressure of spring |83 acts to seat the inlet valve |82.

When the brake cylinder piston |52 is then returned toward its release position upon the release of uid under pressure from chamber |88 through pipe 200 in effecting a release of the brakes, said piston engages the pump piston |65 and forces said piston into chamber |66 to the position shown in the drawing and this movement of the pump piston acts to force lubricant out of chamber |66 past the check valve 205 into passage 201 and from thence to passage |1| and chamber |69a in the brake cylinder body |5|. From passage |1| the lubricant is forced to pipe |12 in the non-pressure head |54 and from thence through passages |13 and |14 to the annular spaces |15 and |16 wherein the lubricant contacts the piston rod |55 so as to effect lubrication thereof as said rod is moved through the non-pressure head |54 upon operation of the brake cylinder piston |52. The packing cup skirts |51 and |58 act to prevent leakage of lubricant supplied to the annular grooves |15 and |16 out along the piston rod |15.

After the lubricant passages just described are lled with lubricant, the lubricant rises above passage |1| in chamber |69a to above the top of the pipe |18 and then flows down through said pipe into the annular chamber |63 and around the brake cylinder piston |52, so that upon movement of the brake cylinder piston, lubricant in said chamber will be spread upon the wall of the brake cylinder body. The felt ring |64 is provided to absorb and hold a portion of the lubricant supplied to chamber |63 for providing a more uniform application of the lubricant to the cylinder Wall.

It will here be noted that the pump piston |65 is operated upon its intake stroke when the brake cylinder piston |52 moves toward the right hand in applying the brakes and is operated on its pumping stroke by said piston during the nal movement of said piston to release position, and it will further be noted that the skirt 203 of packing cup |6| covers the lower end of pipe 18 before said pump piston is operated to pump lubricant and thus prevents the pumping of lubricant into chamberV |88 at the pressure side of the piston. In other words, the pump piston |65 is not operated to pump lubricant until after the annular chamber |63 in the brake cylinder piston is substantially open to the outlet end of stand pipe |18.

The pipe 18 is provided in chamber |69a in order to prevent lubricant contained therein and in the passage |1| from draining into the pressure chamber |88 when the lower end of said pipe is open thereto at the time the brake cylinder piston |52 is in its application position at the right hand side of the lower end of said pipe.

The passage |81 is provided in the lower .portion of the brake cylinder body |5| to permit any lubricant which may collect in the pressure chamber |88 at the left hand side of the packing cup |6| to drain back into the lubricating reservoir |19. 'I'he passage |81 also has another function in that it permits the iiuid pressure obtained in the pressure chamber |88 in eecting an application of the brakes to act on the body of lubricant in the reservoir |19 and thereby through the pipe |8| and passage |86 on the lubricant in the pump piston chamber |66, thereby balancing substantially the opposing fluid pressures acting on the pump piston |65 in order to facilitate movement thereof by the spring |61 on its suction stroke.

After the lubricant conducting passages in the brake cylinder device are completely filled with a certain amount of lubricant through the chamber |83 around the periphery of the brake cylinder piston |52 and back to the lubricant reservoir |19. In other words, it is intended that the pump ypiston |65 shall upon each pumping stroke circulate some lubricant around the brake cylinder piston |52 and back into the lubricant reservoir |19, so as to provide the most efficient type of lubrication for the brake cylinder piston.

The lubricant reservoir |19 is, as hereinbefore described, secured to the depending boss of the brake cylinderbody |5| so that after the lubricant in said reservoir has been used up, the reservoir may be removed through the medium of a wrench (not shown) adapted to be applied tothe lower end thereof. After the reservoir |19 is removed a cap |93, shown in Fig. 2 of the drawing, is adapted t0 be secured over the open end thereof by screw-threaded engagement, for preventing dirt or other foreign matter from entering the interior of said reservoir. A cap |93 is then removed from another reservoir |19, which has been iilled with lubricant, and this reservoir is then screwed into the depending boss |80 of the brake cylinder device and provides lubricant for further operation thereof. It is, of course, evident that the empty reservoir |19 removed from the brake cylinder could be refilled with lubricant at the time of removal and then reapplied to the brake cylinder if desired, but it is proposed that in actual practice several reservoirs |19, properly filled with lubricant, will be carried by a workman and applied to brake cylinder devices as required to replace empty reservoirs. A'cap |93 is provided on each of the filled reservoirs |19 not only to prevent dirt entering the reservoirs, but also to hold the lubricant in the reservoirs.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: i

l. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing., a piston rod carried by said piston and slidably mounted in said casing, said piston having av release position and being movable therefrom to effect an application of the brakes, said piston also having an annular lubricant receiving space disposed at the peripheral face thereof, a lubricant conducting passage in said casing adapted to communicate with said space in the release position of said piston, another lubricant conducting passage leading to the peripheral bearing of said rod in said casing, a source of lubricant, and a pump means operable upon movement of said piston from release position to effect the supply of lubricant from said source to a chamber and operable upon movement of said piston to release position to force lubricant from said chamber into and through said passages to said space and the bearing of said rod in said casing.

2. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having at one sideanon-pressure chamber and at the opposite side a pressure chamber to which fluid under pressure is adapted to be supplied for effecting movement of said piston in one direction to effect an application of brakes and from which uid under pressure is adapted to be vented to permit movement of said piston in the opposite directionvto effect a release of brakes, a source of lubricant adapted to be subjected to the pressure of fluid in said pressure chamber, a pump piston subject to the opposing fluid pressures in said pressure chamber and source of lubricant, a spring acting on said lpump piston for operating same to effect the suply of lubricant from said source to a chamber upon movement of said brake cylinder piston in the direction to apply the brakes, said pump piston being movable by said brake cylinder piston upon movement in the direction for releasing the brakes to operate said pump piston to force lubricant from said chamber to the moving parts of said device.

3. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having a release position and movable therefrom by fluid under pressure to effect an application of brakes, a lubricant reservoir carrying a quantity of lubricant removably secured to said casing, said casing having passages for conducting lubricant to the moving parts of said device. means operative upon movement of said piston in one direction to effect a supply of lubricant from said reservoir to a chamber and upon movement of said piston in the opposite direction to force the lubricant under pressure from said chamber into said passages; and means operative upon a predetermined increase in the pressure of lubricant forced into said passages to open communication therefrom to said reservoir to permit release of lubricant back to said reservoir.

4. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having at one side a pressure chamber to which fluid under pressure is adapted to be supplied to eiect movement of said piston to apply brakes and from which fluid under pressure is adapted to be released to permit movement of said piston to effect a release of brakes, a reservoir carrying a quantity of lubricant secured to said casing withr the space above the lubricant open to said pressure chamber at the lowermost portion thereof, and 4means operative upon movement of said piston in applying the brakes to effect charging of a chamber with lubricant from said reservoir and in releasing the brakes to force the lubricant from said chamber to the moving parts of said device for effecting lubrication thereof.

5. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having a release position and movable therefrom by iiuid under pressure to effect an application of brakes, said piston having an annular lubricant carrying chamber at the peripheral face thereof, said casing having a port communicating with said chamber in the release position of said piston, said casing also having a passage connected to said port, a source of lubricant, means operative upon movement of said piston in a` direction away from release position to effect charging of a chamber with lubricant from said source and upon movement in the opposite direction into release position to force 1ubricant from said chamber to said passage, and a, check valve for preventing flow of lubricant through said port in a direction toward said passage.

6. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having a release position and movable therefrom by uid under pressure to effect an application of brakes, said casing having passages for conveying lubricant to the moving parts of said device, means for preventing leakage of lubricant at the moving parts of said device, means operative upon movement of said piston to supply lubricant under pressure to said passages, and means operative upon a predetermined increase in the pressure of lubricant in said passages to release lubricant therefrom.

.7. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and havinga release position and movable therefrom by fluid under pressure to ei'- fect an application of brakes, a rod secured -to said piston and slidably mounted in a bore in said casing, said piston having an annular lubrf` cant receiving chamber at the peripheral face thereof, said casing having a passage through which lubricant is adapted to be supplied to the bearing of said rod, said casing also having a port communicating with said passage and in release position of said piston with said chamber, means operative upon movement of said piston for supplying lubricant under pressure to said passage, and means for preventing the supply of lubricant through said port until said passage is substantially charged with lubricant.

8. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having a release positionl and movable therefrom by fluid under pressure to effect an application of brakes, a rod secured to said piston and slidably mounted in a bore in said casing, said piston having an annular lubricant receiving chamber at the peripheral face thereof, said casing having a passage through which lubricant is adapted to be supplied to the bearing of said rod, said casing also having a port communicating with said passage and in release position of said piston with said chamber, means operative upon movement of said piston for supplying lubricant under pressure to said passage, the inlet opening of said port to said passage being so positioned that lubricant is prevented from flowing through said port until said passage is substantially filled with lubricant.

9. A brake cylinder device comprising in combination, a cylinder, a pressure head secured to one end of said cylinder, a non-pressure head secured to the opposite end of said cylinder, a brake cylinder piston slidably mounted in said cylinder, a rod carried by said piston and slidably mounted in a bore through said non-pressure head, a reservoir containing a quantity of lubricant removably connected to said device, a

pump piston slidably mounted in said pressurev -eil'ecting operation of said pump piston upon movement of said brake cylinder piston from release position and the subsequent movement of said brake cylinder piston back to release position.

10. A brake cylinder device comprising in combination, a casing, a piston slidably mounted in said casing and having at one side a pressure chamber to which fluid under pressure is adapted to be supplied to effect movement of said piston to apply brakes and from which fluid under pressure is adapted to be released to permit movement of said piston to eiect a release of brakes, a reservoir carrying a quantity of lubricant secured to said casing with the space above the lubricant open to said pressure chamber, and means operative upon movement of said piston in applying the brakes to effect charging of a chamber with lubricant from said reservoir and in releasing .the brakes to force the lubricant from said chamber to the moving parts of said device for effecting lubrication thereof.

11. A brake cylinder device comprising in combination, a casing having a bore, a piston slidably mounted in said bore and having a release position and movable therefrom by fluid u'nder pressure to effect an application of the brakes, a reservoir containing a quantity of lubricant associated with said casing and open to the lowermost portion of said bore at the pressure side of said piston in its release position, said piston having an annular groove in the peripheral face thereof and one side of said groove being open to the wall of said bore, said casing having a passage connecting said groove to said reservoir inthe release position of said piston, andv a pump operative upon movement of said piston from release position to supply lubricant from said reservoir to said chamber, said pump being operative by said piston upon subsequent movement to release positionto force lubricant from said chamber into said groove around said piston and from thence through said passage to said reservoir.

BURTON S. A la .i A Nl 

